How do you use slopes to write the proportion to find the value of x for this problem...

Question

(4,5), (1,2), (x,0)

please show your work and explain
thx

Answer 1

Assuming the three points lie on a single line, then since the slope is constant,

(5-2)/(4-1) = (2-0)/(1-x)
x = -1

Note that x changes by the same amount as y between points.

Since y changed by -2, from 2 to 0,
x changed by -2, from 1 to -1.